This invention relates to a piston and rod assembly, and in particular to an improvement in such an assembly utilized in hydraulic cylinders.
Various constructions are known for connecting a piston to a rod. Whatever connection is utilized, the ultimate goal is to prevent any relative movement between the piston and the rod, yet allow the piston to be removed from the rod. One of the most common is a threaded connection.
Another common connection between a piston and a rod is one employing members disposed in a groove in the rod and extending into abutting relationship with the piston. Examples of such assemblies are shown in United States Pat. Nos. 2,998,288 and 3,457,842. In one construction, blocking members are disposed in the groove in the rod and abut the piston for preventing movement of the piston relative to the rod in one direction but utilizes a snap ring for preventing movement of the piston relative to the rod in the opposite direction. The snap ring cannot withstand large forces and, therefore, such an assembly cannot be employed where larger forces are exerted on the piston tending to urge it to move relative to the rod axially in both directions. The other assembly includes a bearing band disposed annularly about the locking members to retain the locking members in the groove in the rod. Thus, the assembly is no more secure or strong than the strength of the bearing bands.